Relay.



C. B. HARLOW.

RELAY.

APPLICATION FILED AUG.28, I917.

4 EJ W UNITED STATES PATENT OFFICE.

CLARENCE B. HARLOW. OF CHICAGO, ILLINOIS, ASSIGNOR 'IO BENJAMIN ELECTRIC MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

RELAY.

Specification of Letters Patent.

Patented July 16, 1918.

Application filed August 28, 1917. Serial No. 188,577.

To all whom it may concern.-

Be it known that I, CLARENCE B. HARLOW, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Relays, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates to telephone signaling relays intended particularly for transferring a subscribers call from the telephone line to a high-tension or other powerful industrial calling signal.

In factories, mines, quarries, boiler factories, or wherever the noises incident to industry rise to a considerable volume, the ordinary telephone bell is not effective as a calling signal. It cannot be heard above the din of the machinery. The result is lost telephone calls, lost business, lost money in time of operatives and equipment, tedious waiting and annoyance gene-rally. Attempts have been made to overcome the difficulty by supplying the telephone line with large extension gongs. But these also are ineffective because not of sufficient tone volume. The ringing currents sent over the telephone line are not of sufficient strength to operate effectively the necessarily heavy vibrating parts of such gongs, and the signals given are Weak.

It Will be understood that telephone lines running to points where such signals are frequently desired may be miles in length, as in the case of distant mines, quarries, isolated plants and the like, and that not one subscribers station only, but several may be connected along the line. At each station there is a bell. The ringing current which is sent out from the central office must operate all these bells. Obviously this (-ur rent is weakened for each bell by both the resistance of the long line and its division among the bells. It is not practical, therefore, to operate an industrial signal directly from a telephone line.

In order to overcome these and other difliculties and to provide for operating a satisfactory industrial signal from a telephone line without deterioration of the conversation to be carried on over the line, or the.

usual signaling, even though there be several parties on the line and the line be long and therefore of high resistance, and without the necessity of reconstructing the telephone lines or the central oflice apparatus or the provision of additional equipment to be supervised by the operators, to the detriment of the service generally, I provide a relay at the sub-station of the telephone line where the industrial signal is to be located, which relay is responsive to the ringing current sent out to that sub-station in the ordinary course of calling by the operator, and controls an auxiliary circuit of high tension or sufficient power effectively to operate an industrial signal located therein. This auX- iliary circuit is preferably the lightin or power circuit on the premises, whic is usually of high voltage and ordinarily cannot be used in conjunction with the telephone line and apparatus, but which is capable of furnishing ample current to operate effectively an industrial signal. The signal itself is preferably an electric horn of loud tone and large volume, which the car can instantly recognize above the din of the machinery or other noise present.

The relay is important in that it forms the connecting medium between the telephone system and lighting or power circuits, and must perform its intended functions Without detriment to the normal service in either system or interference one with the other. These two systems are radically different in characteristics. The one is delicate and liable to derangement and impairment of its service; the other is rough and rugged and of unlimited power. The difiiculty is accentuated because the relay must derive its power from the weaker current, which is alternating in character, to enable it to do its work in the high power circuit Where the contacts must be handled with force and precision.

To be dependable for the purpose intended, the relay should respond to the feeblest ringing current reaching its station. Its frequent use on party lines dictates that it shall not attempt to increase its own current by robbing the other stations. It is therefore made of the same eflective, resistance to the alternating ringing currents as the other signals, such asbells or what not, on the line, to prevent such robbing, and at the same time insure receiving its own full share.

The relay is constructed to choke and prevent the passage of voice currents, which are also alternating in character, while at the same time perniittin the free passage of the alternating ringlng current. It may therefore be connected across the line permanently, the most desirable and approved arrangement, without deterioration of the conversational or signaling qualities of the line. rent of the relay is alternating and compara tively weak, the high-voltage current-carrying parts of the relay must be of sufiicient weight and strength to carry safely such current, and the contacts be firmly closed and held so closed during the flow of the ringing current on the telephone line, and

then be suddenly opened to break this cir-,

cuit without damage. Moreover, the armature of the relay should not chatter or vibrate sufiiciently to open the circuit under the influence of the alternating current, or the operation of the industrial signal, as well as the relay, will be defective.

In the particular embodiment illustrated herein, the magnet of the relay is of substantially triangular or U-shape-with converging legs the free ends of which form the two poles, the coils of the rela being mounted on the converging legs. his construction afiords the maximum concentration of the external magnetic field, the maximum separation of the coils and the minimum length of magnetic circuit. Thus, a small and light armature can be efliciently used, leakage between the coils is reduced, and the reluctance of the magnet circuit is decreased. The magnet core is built up of a plurality of sheet metal punchings of the required triangular form placed on top of each other and all bolted securely together and to the base. There are no air gaps or breaks in the magnetic circuit from end to end of the core, and the laminations of the latter prevent eddy currents and the loss of energy in heat. The efliciency of the magnet is thus further increased.

A comparatively small and light arma-' ture poised in front of the magnet poles and" operating in the concentrated magnetic field serves to close the contacts of the high-tension circuit, and to keep them closed during the continuance of the ringing current. Upon failure of the calling current, the armature falls back quickly, breaking the circuit and preventing damage to the contacts or relay from the high-tension current. This armature is made light and is preferably so poised as practically to eliminate Again, although the energizing cur- Figure l is a diagrammatic view of a telephone system'embodying my invention;

Fig. 2 is a perspective view of the relay with the cover in place;

Fig. 3 is a face view of the relay with the cover in cross-section and its top removed;

Fig. 4: is an edge view of the same, the cover and other detailed parts being in cross-section I 'Fig. 5 is a perspective view of the armature and its mounting plate; and

Fig. 6 is a bottom plan view of the insulating terminal base for the power circuit leading-in conductors.

In Fig. 1, L represents a party telephone line extending to some distance from the central oiiice or exchange. The line terminates in one or more of the usual jacks J on the switchboard at the central office, where the operators are provided with cord-circuits G, enabling them by means of the plugs P to connect their telephones and the ringing generator with the spring jacks and corresponding telephone lines, and to connect the various lines together for conversation.

Such a ringing current generator is common to the whole exchange or va large part of it, and generates alternating current to which the bells at the various subscribers stations are responsive. particular subscriber being received by an operator, she inserts the opposite plug P of the 'cord circuit which she happens to be using to receive the call, into the spring jack J of the line on which the desired party is located, and depresses her ringing key is.

This connects the generator Gr with the line and sends out over it the ringing current. On the particular line shown, any number of parties may be located, but three being shown. At each subscribers station there are located the usual transmitter 25 and receiver 7', the signaling bell b and condenser c, the latter two being bridged across the line, in series with each other.

If the last shown substation. for instance, be located in a factory or other place where the bell cannot be readily heard, the relay R is employed, this being also bridged across the line together with condenser 0 or, if preferred, the condenser c, the bell 6 being retained or not, as desired. 7

This relay controls the circuit of the hightension industrial signal S located on the lighting or other, high-tension power circuit Q on the premises where the telephone substation is located. The relay, as herein Upon a call for a explained, is respmisive to the alternating ringing current on the telephone line, and closes and keeps closed the high-tension circuit during the flow of ringing current. At the cessation of the latter the relay contacts are automatically restored and the signal stops.

This relay is illustrated in detail in the remaining figures. I provide an insulating base 10, preferably of porcelain, having an annular shoulder 11,011 which base is mounted an electromagnet comprising a plurality of substantially U-shaped 01' triangular laminations laid fiatwise or stacked one on top of the other to form the core 12 of the magnet, These laminations, which are preferably punched or stamped from sheet metal of suitable quality, are clamped directly upon each other and to the insulating base 10 by means of a clamping plate 13 extending across the top of the base or rear portion of the core, by two screws or bolts 14 which pass through the two ends of the clamping plate, the corners of the laminations and the base 10, and have nuts on their opposite ends, these nuts being countersunk in suit able recesses, as shown in Fig. 4, in the bot tom or opposite side of the base 10; Magnet windings or coils 15 surround the converging legs of the core 12, and the base 10 is recessed, as at 16, to accommodate the lower or inner edge portions'of these windings.

This triangular form of core permits the poles to be brought close together to concentrate the magnetic flux upon a comparatively small and light armature while at the same time the divergence of the coils prevents excessive leakage across from one to the other. The desired cross-section of iron core and the number of turns 'of wire in the windings are obtained while still keeping the poles close together, by building up the number of laminations so that the core is rectangular in cross-section with the inner long sides of the rectangular poles adjacent each other, and by winding the magnets in the same rectangular form, instead of circular as in the ordinary magnet. These coils are of fine wire and are wound on fiber spools, the ends of which are seen at 17, of a size and central opening to fit closely over the legs of the core, and while kept as close together as possible the separation of their free ends is such that the coils may be pushed or driven into position on the legs one after the other. Again, the triangular form of core affords the shortest magnetic path having the above mentioned characteristics. thus keeping the reluctance of the circuit to a minimum, and the base portion afl'ords a convenient means of clamping the laminations together and to the base and, as hereinafter explained, a convenient support and mounting for the relay contact springs. The laminations prevent the formation of eddy currents and consequent wastage of energy by heat in the core, and being jointless from pole to pole still further reduces the reluctance.

The armature of the magnet consists of a narrow flat iron strip 18 of suitable qual-- ity, having its-upper end 19 bent diagonally outward, to form a cam member, and its lower or opposite end turned backwardly to form a hinge 20. This armature is hingedly or pivotally supported upon a pivot pin 21 extending between a pair of rearwardly turned lugs 22 on supporting plate 23. The plate 23 likewise has a lug 24, through which extends an adjusting. screw 25 forming an adjustable abutment or back stop for the pivoted armature 18. This plate 23 is positioned in a countersunk opening 26 in the insulating base, and its lugs' 22 extend into an extension of the recess 16, whereby the side walls of the cavity prevent the lateral displacement of the hinge or pivot pin 21 and its dropping out of position between the two lugs. The plate 23 is secured in position by two screws 27 through the base and threading into the plate. The apertures for these screws are elongated slightly to afiord means for adjusting the plate back and forth toward the magnet poles to "ary the position of the armature support with reference to the poles. The armature is provided with a non-magnetic stop 18 to prevent its sticking to the hole pieces.

By this adjustment of the supporting pivot plate together with the adjustable back stop screw 25, the armature can be so positionedwith respect to the poles of the magnet as practically to eliminate the effect of gravity on the action of the armature. And this is true even though the relay be placed with its base horizontal. But to further negative the action of gravity in the operation of the relay, I prefer to mount it with the insulating base in a vertical plane with the contact springs, hereinafter described, extending in a horizontal direction. I also prefer, as shown. to dispense with a restoring spring or springs, 7901* se, for the armature, the inner or lower contact spring being relied on for that purpose.

An additional advantage of the adjustment of the position of the armature independently of the magnet is that errors of inanufzwture are taken care of and use of a porcelain or other molded base is permitted. A molded base, such as porcelain, is preferable, and in some localities is required by the underwriters on account of the high voltage circuits with which the relay is employed, but on account of inaccuracies of manufacture has not been considered prac ticable for devices of this nature without the provision of an intermediate metallic or similar base which can be carefully machined and on which the parts can be accurately assembled. By my construction, however, the base may be manufactured in the usual way and the parts assembled directly thereon and then brought into accurate and satisfactory adjustment, thus dispensing with auxiliary bases or other undesirable features.

On the clamping plate 13 I mount a pair of contact springs or arms 28 and 29, to open and close the high-tension circuit. They are clamped at their rear ends between insulating washers 30 by means of screws 31 passing first through a metallic washer plate 32, then through the insulating washers, and threading into the clamping plate 13, the springs being enlarged at this clamping portion'to substantially the same size as the washers 30 and 32 and suitable insulating bushings (not shown) lining the screw holes and extending through the washers 30 and springs 28 and-29, to insulate the screws from the springs. Each of the springs is provided with a rearwardly extending projection 33 offset on opposite sides, as shown, and are connected respectively by insulated conductors 34 with the terminal clips 35 located on the insulating member 36. The conductors 34 are preferably soldered at each end to the corresponding member. The terminal clips 35 are suitably secured to the insulating member 36 by hollow metal rivets having their lower ends countersunk in the lower face of the insulation and are provided with upturned projections at their rear ends and binding screws 37 by means of which the leadingin conductors of the hightension circuit may be secured mechanically and electrically to said clips.

This insulating terminal support is secured to the porcelain base 10 by two screwbolts 38, the nuts of which are countersunk in the bottom of the base. Projections are formed on the lower face of the support 36 to hold it up away from the porcelain base, two of these, 39, surrounding the bolts 38, and the third, 40, being arc-shaped and running along the shoulder 11 of the base and extending the width of the raised portion 41 of said support. This raised portion afi'ords an insulating housing and support for the leading-in conductors. Such conductors ordinarily have an insulating covering which must be stripped off at the ends connected from the portion 41 between the clips 35.

The member 36 may be made of molded material, such as bakelite, or in other ways.

The contact springs 28 and 29 project. forwardly over the magnet and at their forward ends are provided with contact polnts- 45. The lower or inner spring projects beyond the end of the magnet, as at 46, and is slightly bent up diagonally to form a cam portion which is adapted to be engaged by an insulating button 47, preferably of hard rubber, carried by the angle portion 19 of the armature.

When the armature 18 is attracted, the button 47 engages the inclined end 46 of the spring 29, raising it and closing the contacts 45 in the high tension circuit.

When the ringing current ceases in the magnet the spring 29 forces the armature back to its normal unattracted position, openingthe circuit.

The springs are adjusted so that when the armature is attracted to its full forward position, the outer spring 28 is slightly raised. As a result there is a slight followup movement of said spring when the armature starts to return. If, therefore, there should be a tendency of the armature to release or move backwardly at the reversal of direction of the energizing cur rent, such follow-up action will prevent the separation of the contacts 45 so that the circuit therethrough will be maintained closed. This action may be assisted also by the resiliency of the inclined end of the spring.

Suitable binding-post plates 48 are mounted on the top face ofthe base on either side of the forward end of the magnet and are connected by conductors 49 with the outer ends of the windings 15, their inner ends being connected together. These plates carry binding-posts 50 and the base 10 is providedwith holes 51 in close proximity to each of the binding posts through which the leading-in wires fromthe telephone branch may be brought in. Grooves 52 in the bottom of the base 10 lead from the holes 51 to the edge of the base so that thewires will not project beyond the bottom face.

The relay is secured to its support by screws passing through holes 53 in the base and threading intothe support.

A sheet metal cover 54 fits down over the working parts of the relay and at its edge engages the annular shoulder 11. A portion of the edge is cut out to fit over the raised projection 41 of the insulating plate 36. The cover is held in position by means of suitable securing screws 55 threading into posts 56 secured in turn to the insulating base by screws extending from the bottom through the base and into the other ends of the posts.

By this construction and arrangement, the

relay may be installed in any convenient location and may even be exposed to the elements or in damp places,-such as mines or the like, without detriment to its operation or to its insulating qualities. When connected to the telephone line and to the signal circuit, it will close the signal circuit in response to the ordinary telephone ringing current on the line, and thus operate the auxiliary signal. The sensitiveness of the relay enables it to be satisfactorily used where the ringing current is extremely Weak. There is also a considerable saving in-copper wire or magnet winding by this construction over other types of alternating current relays; for example, as compared with some types of alternating current relays there is only about onefifth of the copper wire used and a relay two or three times as efficient is obtained.

Various modifications may be made without departing from the spirit or scope of my invention as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. An alternating-cin'rent signaling relay for telephone lines having, in combination, a U-shaped converging-legged core, a Winding upon each leg, an armature opposite the free ends of said legs and attracted by the magnetism produced by the alternating ringing current through said coils, and circuit-controlling contacts operated by said armature and maintained in operating condition during the flow of said ringing current and automatically restored upon cessation thereof.

2. An alternating-current signaling relay for telephone lines having, in combination, a U-shaped converging-legged core, a winding upon each leg, an armature poised in front of the ends of said legs, and circuitcontrolling contact springs having their free ends in proximity to said armature. said armature cooperating with the free ends of said springs to control the circuit therethrough.

3. An alternating-current signaling relay for telephone lines having, in combination. a U-shaped converging-legged core, a winding upon each leg, circuit-controlling contact springs extending forwardly to the front end of the magnet, one of said springs having an upturned end, and an armature poised in front of the ends of said core legs, with its free end cooperating with the said upturned end of the spring to operate the Sit-I118.

4. An alternating-current signaling relay for telephone lines having, in combination, a U-shaped converging-legged core, a wind' ing upon each leg, a set of contact springs mounted on said core between said windings and extending forwardly to the front end of the magnet, one of said springs having an angular extension, an armature in front of said core ends pivoted at one end and having an angular extension at the opposite end cooperating with said extension of said spring to operate the latter to control the circuit.

5. An alternating-current signaling relay for telephone lines having, in combination, a U-shaped converging-legged core, a winding upon each leg, an armature in front of the ends of said core pivoted at one end and having an angular extension at the other, an insulating cam button carried by Said angular extension, a pair of contact springs secured to the rear central portion of said core and having their forward free ends extending into proximity with said armature-the inner spring havlng an angular extension corresponding to the extension of said armature and engaged by said cam button when the armature is attracted to lift said spring and thereby to close their contacts.

6. An alternating-current signaling relay for telephone lines having, in combination, a U-shaped converging-legged core, magnet coils on said legs extending substantially the length thereof, the free ends of said legs being close together to concentrate the external magnetic field and separated sufficiently to permit slipping the magnet coils on to the legs, the divergence of the coils toward their opposite ends preventing magnetic leaking therebetween, an armature in front of said free ends arranged to be attracted by the magnetism produced by said coils and to be maintained in attracted position during the continuance of the ringing current, and contacts controlled by said armature.

7. In a relay, the combination with an insulating base, of a magnet core mounted thereon comprising a plurality of converging-legged U-shaped laminations placed fiatwise one upon the other and clamped to said base by screws passing therethrough and through the base, windings surrounding the legs of said magnet core, a pair of circuitcontrolling springs mounted on the base portion of said magnet core and projecting forwardly along the top thereof, one of said springs projecting beyond the end of th magnet core, and an armature pivoted in front of said magnet core and having at its upper end means engaging the projection on one of said springs for operating the same to close the contacts when the armature is at tracted by its magnet.

8. In a relay, the combination with an insulating base, of a magnet mounted on said base, a securing plate clamped upon said base, a pair of lugs formed on said plate and turned at right angles to the plate, a pivot pin secured between-the said lugs, an armature for the magnet pivotally mounted on said pivot pin, a second angularly turned lug on said plate, and an adjustable stop vfor said armature carried by said lug.

9. In a relay, the combination with an insulating base, of a magnet mounted on said base, a securing plate for said base, a pair of lugs formed on said plate angularly turned downward, said insulating base having a re cess for the reception of said lugs of sufficient width to permit the lugs to pass therein, a pivot pin carried by said lugs and secured against lateral displacement by the walls of said recess, and an armature for said magnet mounted on said pivot pin.

10. In a relay, the combination with an insulating base, of a magnet core mounted thereon comprising a plurality of U-shaped laminations with converging legs placed fiatwise one upon the other and clamped to said base, windings surrounding the legs of said magnet core, said base being recessed to accommodate the lower edges of said windings whereby the laminations can be clamped directly to the base, and an armature for said magnet.

11. In a relay, the combination with an I magnet, a supportffor said armature mounted on said insulating base independently of the said magnet and adjustably secured thereto.

12. In a relay, the combination with an insulating base, of a magnet core comprising a plurality of triangular lan'iinations placed one upon the other flatwise on said base, a clamping plate on the top of said magnet core clamping it in position on said base, a pair of contact-carrying springs mounted at their rear ends upon said clamping plate, insulating strips interposed between said 'sprin s and between the bottommost spring and t e clamping plate, said springs projecting forwardly along the top of said mag net core, and an armature for the magnet at its forward end arranged to operate said springs to open and close the circuit.

In witness whereof, I have hereunto subscribed my name.

GLARENGE B. HARLOW. 

